I own a slightly modified moped (scooter in the USA) with a 72cc bore, stock crank ratio with a high performance pipe, 28mm carb, intake, pulley, weights, etc. Keep in mind that my bike has no power valves. I've been on the lookout for some oils that perform well and look good after a teardown. I've only used maybe a handful so I'd like to share my experiences with them. Castrol 2T Oil: This is the worst stuff I've ever used, it's blue in color, smells bad and leaves a ton of carbon deposits on the cylinder head, piston crown and especially the exhaust port. I used it as a cheap alternative towards trying something new, I wouldn't recommend using this even as a break-in oil. The oil ratio used was 32:1 with the jetting adjusted for it. Motul 800: This is an ester-based synthetic that smells really good with a fruit punch syrup-looking oil. It's very pricey at $19 a quart here so it's the most expensive of the bunch I'll be reviewing. I have to say that it works really well and the appearance during the teardown showed a very clean piston, head and exhaust port. The oil ratio was 32:1 during the testing. This easily ties for first place in terms of how well it works, however because the stores here charge so much for it, it ranks as 3rd place overall. AMSOIL Dominator: This was the cheapest synthetic I found that's a well known brand at just under $11 a bottle. It smells really bad like a solvent and it's very thin. I've tried it at 32:1 initially (bottle recommends 50:1) and it ran like [censored] even with the jetting set for it. It developed a lot of hard carbon deposits around the exhaust port at this ratio so we backed it down to 50:1. At the recommended ratio, it ran cleaner, we had to downjet some to compensate and the motor ran "crisper". I've learned that with full synthetics like AMSOIL, it's probably best not to go much beyond 50:1, with 40:1 probably being the most that you should use. As nervous as 50:1 makes me with other oils, I completely trust AMSOIL Dominator 2-Cycle at 50:1. The teardown shows up very clean with no deposits on the cylinder head, piston crown, ring grooves and exhaust port. This is my 2nd choice for oils. Maxima Castor 927: This is a bean oil, not a full synthetic. It is the thickest of the bunch at SAE 40 but it smells absolutely fantastic! I originally thought that the bike would run like [censored] using a premix oil this thick but it ended up being very good. The motor smokes a lot but at least it smells sweet (literally). I used 32:1 and the jetting was set for it and ran great. It ran very smooth as opposed to the crispy nature of using AMSOIL Dominator. The teardown was amazing, zero deposits around the spark plug, piston crown, ring grooves, head and exhaust port. One of the best parts about this oil is that if it's overheated, unlike other oils (even full syns), it doesn't form hard carbon deposits, it forms an even better lubricant that leaves varnish as a byproduct which is actually a very good lubricant. This is very bad for motors with power valves but mopeds don't have them. The only negative about this oil is that it tends to plug your exhaust pipe/silencer as a result of all that smoke, however I'll gladly deal with that rather than deal with a clean pipe/silencer with carbon on the bore/ports/piston/head. This is my favorite oil of the ones reviewed, however Dominator is a very close second place. Summary: Castrol 2T: Junk, don't use this, ever. Motul 800: Probably the best if you can find it for under $15 a quart. It's just very expensive where I am, not sure why. AMSOIL Dominator: An excellent synthetic that should be used at or close to 50:1, don't go 32:1 with this as it'll leave a lot of deposits. Smells bad but protects very well and leaves hardly any deposits even after 3000 miles of use. Price per quart is very hard to beat making this an excellent value. Castor 927: Thick oil that smells great when burned. This will provide the best chance at protection if you're running lean since castor oils gets better as temperatures climb. Your engine will be spotless, no carbon will form from using this. Your pipe/silencer will plug up faster. Not recommended for use where it gets extremely cold.